Biomedical support of man in space

Pendergast, David R.; Olszowka, Albert J.; Rokitka, M. A.; Farhi, Leon E.

doi:10.1016/0094-5765(88)90021-5

Cited by 1 publication

(1 citation statement)

References 17 publications

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“…Q _ is only 20% of its 1 Gz value at 3 Gz, despite a 50% increase in heart rate (Boutellier et al1985;Pendergast et al 1988). Water immersion to heart level should partially cancel the effects of gravity on systemic circulation.…”

Section: Effects Of Gravity or Simulations Of Changes In Gravitymentioning

confidence: 96%

Cardiac output: a view from Buffalo

Olszowka

Shykoff

Pendergast

et al. 2003

European Journal of Applied Physiology

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Cardiac output (Q) is a primary determinant of blood pressure and O2 delivery and is critical in the maintenance of homeostasis, particularly during environmental stress. Cardiac output can be determined invasively in patients; however, indirect methods are required for other situations. Soluble gas techniques are widely used to determine Q. Historically, measurements during a breathhold, prolonged expiration and rebreathing to CO2 equilibrium have been used; however, with limitations, especially during stress. Farhi and co-workers developed a single-step CO2 rebreathing method, which was subsequently revised by his group, and has been shown to be valid (compared to direct measures) and reliable. Carbon dioxide output (VCO2), partial pressure of arterial CO2 (PaCO2), and partial pressure of mixed venous CO2 (Pv(CO2)) are determined during 12-25 s of rebreathing, using the appropriate tidal volume, and Q is calculated. This method has the utility to provide accurate data in laboratory and field experiments during exercise, increased and micro-gravity, water immersion, lower body pressure, head-down tilt, and changes in gas composition and pressure. Utilizing the Buffalo CO2 rebreathing method it has been shown that the Q can adjust to a wide range of changes in environments maintaining blood pressure and O2 delivery at rest and during exercise.

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Section: Effects Of Gravity or Simulations Of Changes In Gravitymentioning

confidence: 96%